Valid command

If you don t close a file before ending the program, you can run into big problems. A disk drive has its own microprocessor, which keeps track of open files. If you open a file, write to it, and turn off your computer without closing the file, the result is a "poison" file, which can corrupt other files on the disk. Poison files are marked in the directory with an asterisk. You should never scratch a poison file you have to use the Validate command to get rid of it. Before you end a program, be certain to close all files. 

An abort should only be set into motion by the issuance of a valid abort command from an authorized entity. This requirement is particularly germane to unmanned systems (UMSs). In a manned system, the authorized entity is generally the official operator however, in a UMS much planning must go into determining what constitutes a valid command and a valid controller (authorized entity) because it may be possible for an unauthorized entity to take control of the UMS. 

Anomalous behavior is deviation from a general rule or regime it is inconsistent behavior deviating from what is usual, normal, or expected. In systems applications, anomalous behavior is behavior of an item that is not in accordance with the documented requirements or specifications for the item. It is unexpected behavior, and it is generally undesired behavior. System safety is concerned with anomalous behavior because it can typically be the cause of a mishap, or be part of a sequence of events leading to a mishap. Safety HA typically looks for anomalous behavior that is safety-essential or safety-critical in outcome. When performing an HA, potential anomalous behavior should be considered in hardware actions, hardware functions, software functions, and human tasks. For example, inadvertent rudder movement on an aircraft, without a valid command to move, is considered anomalous behavior with safety significance. 

Authorization rules should be designed into the system. As UMSs evolve and increase in their level of autonomy, a system operator or human controller may not be a valid assumption control may be completely relinquished to the UMS. Systems may use man-to-machine or machine-to-machine control. In this context, the term authorized entity is used to denote the entity which, by design, exercises immediate control over the UMS. The term is used to denote two methods of valid control human or machine. A system safety design goal should be that the system, manned or unmanned, shall be designed to only respond to valid commands from the authorized entity or entities in order to preclude intrusion by hackers or counterfeiters. 

A valid command is a command that meets the following criteria ... 

The arrow above is valid, because the two commandments were not violated. 

Neither of these structures violates the two commandments, so both structures above are valid resonance structures. (However, the bottom structure, although valid, is not a significant resonance structure. In the next section, we will see how to determine which resonance structures are significant and which are not.)... 

Air Force. 1990. Development and validation of methods for applying pharmacokinetic data in risk assessment Volume n. Trichloroethylene. Wright-Patterson Air Force Base, OH U.S. Air Force, Air Force Systems Command, Harry G. Armstrong Medical Research Laboratory, Human Systems Division. NTIS No. AD-A237 366. 

Separating the data transformation into three distinct steps enforces a completely modular software design. In practice, the data transformation is executed via command shell scripts, using freely available software for both the XSLT transformation and XSD validation. The raw data contained in the 39 surveys in the New Brunswick compilation are exported into 7,000 individual KML files, which can be viewed online at http //gdr.nrcan.gc.ca/geochem. 

Note that Matlab directly adds/subtracts a single scalar element-wise to/from matrices. Suppose you want to subtract element foi,2 (a scalar) from all elements of matrix A. A valid Matlab command would be ... 

The Brady Act was challenged in court, but only the part requiring state officials to carry out the back ound checks was overturned by the Supreme Court in 1997 in Printz v. U.S., on the grounds that Congress lacked the power to commandeer the services of local officials. This decision would have little impact because the Brady Act already had a provision that after five years (in 1998) the waiting period would be replaced by a computerized national instant check system that would verify a gun purchaser in much the same way that stores validate credit cards. 

Note that VI is not a valid expression for the Trace command. It is used only for clarity. Instead of VI you would have to enter V(Rl 1). Note that V(R 1 1) is listed as one of the choices in the Add Traces dialog box. 

Software is not a physical entity and, unlike some hardware failures, software failures occur without advanced warning. One of the most common software failures is branching, that is, the ability to execute alternative series of commands based on differing inputs. The software branching capacity makes the commands extremely complex and difficult to validate once errors occur as an answer of a specific input, and until the introduction of that specific input error has not been detected. Software input can be almost any data and, and since it is impossible to introduce all data into a software, validation of data is extremely difficult. Thus, results are considered to be of high confidence level. The majority of software problems occur as a consequence of errors in the software design and development and are not directly related to the software manufacture. It is simple to manufacture several software copies that work perfectly and as the original one. 

The Cooperative is also correct that the District Court in this case had discretion. The Controlled Substances Act vests district courts with jurisdiction to enjoin violations of the Act, 21 U.S.C. 882(a). But a grant of jurisdiction to issue [equitable relief] hardly suggests an absolute duty to do so under any and all circumstances, Hecht, supra, at 329 (emphasis omitted). Because the District Court s use of equitable power is not textually required by any clear and valid legislative command, the court did not have to issue an injunction. 

Thus, until quite recently, belief in a Supreme Being was a legal test of valid conscientious objection to military service. The implication was that the individual objector found himself bound to obey a higher echelon of command than the President and Congress. The... 

This does not violate either of the two commandments. We did not break any single bonds and we did not violate the octet rule. So this is a valid structure. Notice that we cannot move the lone pair in another direction, because then we would be violating the octet rule ... 

Not all resonance structures are always important. Although there are often many valid resonance structures for a single compound (meaning that those structures do not violate the two commandments), usually many of these resonance structures are not significant. For example, the following resonance structures are not significant even though they are valid structures ... 

Technically, this is a valid resonance structure, since we have not violated the two commandments. Nevertheless, we do not consider it to be significant because the negative charge is on carbon and the positive charge is on oxygen. 

However, the domino effect would not occur if it could safely be assumed that each thread s data was fully validated before it was output, i.e., was transmitted from one thread to another. (Similarly, the effect would be avoided if a thread could validate its inputs fully.) Such an assumption is in effect made in simple transaction-based systems, in which outputs from the database thread to a user thread are allowed to occur only after a transaction has been committed in response to a user command. Moreover, in such systems the notion of commitment is regarded as absolute, so that once the commitment has been made, there is no going back, i.e., there is no provision for the possibility that a database output (or a user input) was invalid. 

FIG. 8-86 Online partial stroke diagnostic used to validate the operability of a pneumatically operated safety shutdown valve, (a) Input command generated by the diagnostic and resulting travel, (b) Actuator pressure measured over the tested range of travel. 

The Library Studio Developer s Kit further extends Library Studio by embedding Microsoft s Visual Basic for Applications (VBA) into the Library Studio application. With VBA, the user can import data from statistical packages, such as DOE, or export data for further manipulation, such as a bubble point calculation. Additionally, modifications to the Library Studio user interface are possible via custom add-ins, such as commands to produce automated designs or validate a design intended for a particular instrument. 

Appropriate measures must be taken to ensure the validity of the sources for data and commands. Validation of the automatic interfaces, or a check of the input medium in the case of manual inputs, is performed as part of system validation. For example, if several sets of scales are connected to a network, only calibrated scales with the correct weighing range may be accessed. Similarly, it should only be possible to use radio scanners assigned to a particnlar dispensary for weighing raw materials. In addition, personal identification devices (e.g., company identity badges or ID cards that are used in conjunction with a password) should expire after a period and only be issned to authorized users. On expiry such devices should need formal renewal. 

For combined systems, vendor-updated software revisions may be critical, especially if the updated version supplied by the vendor will have an effect on the interface between the vendor s and the user s software (e.g., if the meaning of a macro command has been changed). The user should obtain information from the vendor on how the updated version may affect the interface. The user should also test his or her software after it has been integrated into the vendor s updated standard software. More details are found elsewhere about Standard Operating Procedures (SOPs) for developing and validating simple as well as complex applications software developed in the user s laboratory. ... 

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